In a conventional rotary electric machine used in an electric power steering device or the like, it is necessary to suppress torque ripple, or in other words torque pulsation. For this purpose, a conventional rotary electric machine is driven to rotate by winding two three-phase armature windings by means of concentrated winding around a plurality of teeth formed on a stator core, and supplying currents having a current phase difference from two inverters respectively to the different three-phase armature windings.
Further, this type of rotary electric machine may include a stator having 18 n (where n is an integer no smaller than 1) teeth and a rotor having (18 n±4 n) field poles (see PTL 1 and PTL 2, for example), or may be configured such that two or more armature windings are wound around at least one of each pair of adjacent teeth and the armature windings are respectively connected to different inverters (see PTL 3, for example).